Process for producing an olefin copolymer rubber

ABSTRACT

A process for producing an olefin copolymer rubber by slurry-polymerizing ethylene, at least one α-olefin and at least one non-conjugated diene in a poor solvent for the copolymer in the presence of a catalyst consisting of an organometallic compound (the first component) and a transition metal compound (the second component), characterized by using, an organoaluminum compound as the first component of the catalyst, and using, as the second component, a modified vanadium compound obtained by contacting a vanadium compound with at least one compound selected from the group consisting of the compounds represented by the following formulas: ##STR1## wherein R is a hydrocarbon group of 1 to 20 carbon atoms and X 1 , X 2  and X 3  are independently halogen atoms or alkoxyl groups. This process can prevent a gel from being formed during polymerization.

This is a continuation, of application Ser. No. 850,067, filed Apr. 7,1986, now U.S. Pat. No. 4,695,614, which is a continuation of abandonedapplication Ser. No. 702,062 filed 2/15/85.

This invention relates to a process for producing an olefin copolymerrubber composed of ethylene, at least one α-olefin and at least onenon-conjugated diene (hereinafter the copolymer rubber is referred to asan EPDM). More particularly, this invention relates to a process forproducing an EPDM composed of ethylene, at least one α-olefin and atleast one non-conjugated diene by slurry polymerization while preventinga high molecular weight polymer having a three-dimensional network(hereinafter this polymer is referred to as a gel) from being formed.

It is known to produce a sulfur-vulcanizable EPDM by copolymerization ofethylene, at least one α-olefin and at least one non-conjugated dieneusing a coordination complex catalyst consisting of an organoaluminumcompound and a vanadium compound.

Upon copolymerizing ethylene, an α-olefin and a non-conjugated dienewith such a conventionally known catalyst, a cross-linking reaction iscaused between the residual double bonds of the non-conjugated diene,thereby forming a gel. This gelation is particularly remarkable inslurry polymerization wherein the polymerization is conducted in a poorsolvent while depositing the resulting polymer, and it has heretoforebeen a great obstacle for utilization of numerous advantages of theslurry polymerization.

The gelation brings about the following disadvantages: Thevisco-elasticity of a polymer formed is reduced by the gelation. Thecorss-linked gel cannot be mixed intimately with various chemicals addedto the polymer, and accordingly, when the polymer is extrusion-molded, agel like poppy seeds appears on the surface of the molded article. Thesematters greatly reduce the commercial value of the polymer. Further, thegelation is especially marked in the region of a high Mooney viscosityand a high iodine value, and unless the gelation can be prevented, nopolymers in this region can be produced. Therefore, the region in whichpolymer-production is possible becomes narrow. Furthermore, in the caseof slurry polymerization, it is substantially impossible to remove thegel in a later step, and hence, it is vitally important to cause nogelation.

For prevention of the gelation, it is proposed to lower thepolymerization temperature to, for example, -30° C. or -40° C. or lower;however, this is not recommendable from the standpoint of energyconsumed. Further, the use of a chain transfer agent such as hydrogen,diethylzinc or the like in a large amount is considered; however, inthis case, the control of the molecular weight of a polymer formed issubstantially impossible.

Under such circumstances, the present inventors have conducted extensiveresearch on the prevention of gelation is slurry polymerization. As aresult, it has been found that the use of a novel catalyst obtained bymodifying a conventionally known catalyst with a specific compound,there results in a meritorious effect that no gel is formed even inslurry polymerization.

According to this invention, there is provided an improved process forproducing an EPDM without causing a gelation, comprisingslurry-polymerizing ethylene, at least one α-olefin and at least onenon-conjugated diene in a poor solvent for the EPDM in the presence of acatalyst consisting of an organometallic compound (the first component)and a transition metal compound (the second component), characterized inthat the first component of the catalyst is an organoaluminum compound(A) and the second component is a modified vanadium compound obtained bycontacting a vanadium compound (C) with at least one modifying compound(B) selected from the group consisting of the following three types ofcompounds (I), (II) and (III): ##STR2## wherein R is a hydrocarbon groupof 1 to 20 carbon atoms and X₁, X₂ and X₃ are independently halogenatoms or alkoxyl groups.

The α-olefin has 3 to 12 carbon atoms, and includes specificallypropylene, 1-butene, 4-methylpentene-1, hexene-1, octene-1, and thelike. These may be used alone or in admixture of two or more. Of these,propylene, 1-butene and a mixture thereof are preferred.

The non-conjugated diene includes the following compounds:dicyclopentadiene, tricyclopentadiene, 5-methyl-2,5-norbornadiene,5-methylene-2-norbornene, 5-ethylidene-2-norbornene,5-isopropylidene-2-norbornene, 5-isopropenyl-2-norbornene,5-(1-butenyl)-2-norbornene, cyclooctadiene, vinylcyclohexene,1,5,9-cyclododecatriene, 6-methyl-4,7,8,9-tetrahydroindene,2,2-dicyclopentenyl, trans1,2-divinylcyclobutane, 1,4-hexadiene,2-methyl-1,4hexadiene, 1,6-octadiene, and the like. These may be usedalone or in admixture of two or more. Of these,5-ethyldiene-2-norbornene, dicyclopentadiene and a mixture thereof arepreferred.

The organoaluminum compound (A) used as the first component of thecatalyst includes trialkylaluminums such as triethylaluminum,triisobutylaluminum, trioctylaluminum and the like; dialkylaluminummonohalides such as diethylaluminum monochloride, diethYlaluminummonobromide, diisobutylaluminum monochloride and the like; andalkylaluminum sesquihalides such as ethylaluminum sesquichloride,ethylaluminum sesquibromide, isobutylaluminum sesquichloride,n-butylaluminum sesquibromide and the like. Of these compounds,diethylaluminum monochloride and ethylaluminum sesquichloride areparticularly preferred.

The modifying compound (B) which is one of the second components of thecatalyst is a compound represented by the formula: ##STR3## wherein R,X₁, X₂ and X₃ have the same meanings as defined above, and includesspecifically the following compounds: unsaturated carboxylic acidderivatives belonging to the formula (I) such as cinnamyl chloride orbromide α(or β)chlorocinnamyl chloride or bromide, α,β-dichlorocinnamylchloride, acrylyl chloride or bromide, α,β-dichloroacrylyl chloride orbromide, trichloroacrylyl chloride or bromide, alkyl acrylates, alkylmethacrylates, alkyl cinnamates, crotonyl chloride or bromide,methacrylyl chloride or bromide, dibutyl maleate and the like; alkylsalicylates belonging to the formula (II) such as methyl salicylate,ethyl salicylate, butyl salicylate, octyl salicylate, 2-ethylhexylsalicylate, dodecyl salicylate and the like; trialkyl borates belongingto the formula (III) such as triethyl borate, tributyl borate, trihexylborate, trioctyl borate, tri-2-ethylhexyl borate, tridodecyl borate andthe like. Of these modifying compounds, dibutyl maleate, methylsalicylate and tributyl borate are particularly preferred.

The vanadium compound (C) which is the other second component of thecatalyst includes vanadium tetrachloride, vanadium oxytrichloride,vanadium triacetylacetonate, oxyvanadium diacetylacetonate, a reactionproduct between vanadium oxytrichloride and an alcohol, vanadyltriethoxide, vanadyl tri-n-butoxide, vanadyl di-n-butoxymonochloride,vanadyl ethoxydichloride, etc. Of these compounds, the reaction productbetween vanadium oxytrichloride and an alcohol, vanadium oxytrichlorideand oxyvanadium diacetylacetonate are particularly preferred.

The modification of the vanadium compound with the modifying compoundrepresented by the formula (I), (II) or (III) is conducted by contactingthese compounds under appropriate conditions. For Example, a modifyingagent is added to a vanadium compound placed in a solvent such astoluene or the like with stirring, and the resulting mixture is stirredfor a given period of time. The contact temperature is usually -60° to100° C., preferably -40° to 50° C., and the contact time is not criticaland may be a very short time, for example, 2 to 3 sec or may be 1 week.In either case, the resulting modified compound has the same effect onthe polymarization of the present invention. The amount of the modifyingagent used is preferably 0.05 to 2.0 moles, preferably 0.1 to 1.0 mole,per mole of the vanadium compound.

The above modification may be conducted in the presence of the monomersto be used in the polymerization of the present invention.

Alternatively, a vanadium compound and a modifying agent may becontacted in a pipe, and then, they are continuously fed to thepolymerization system.

As shown in the Examples appearing hereinafter, it is necessary in thisinvention to preliminarily treat a vanadium compound with a modifyingagent, contact the resulting modified vanadium compound with anorgano-aluminum compound to form an active seed and feed the seed to thepolymerization system. Only in this manner, the effect of this inventioncan be achieved.

The poor solvent for the copolymer used in the slurry polymerization ofthis invention includes, for example, propylene, 1-butene, methylenedichloride, methylene dibromide, ethyl chloride and mixtures thereof. Ofthese, propylene and 1-butene which are also reaction monomers areparticularly preferred.

The polymerization can be conducted continuously or batchwise.

The polymerization temperature is usually -50° to 100° C., preferably-20° to 60° C.

The amount of the organoaluminum compound used is 1 to 100 moles,preferably 2 to 30 moles, per mole of the vanadium compound.

This invention will be explained more specifically below referring toExamples, however, the invention is not restricted to the Examples.

EXAMPLE 1 (1) Modification treatment

Vanadium oxytrichloride (VOCl₃) was modified with dibutylmaleic acid(DBM) as follows: A flask was sufficiently dried and purged withnitrogen. In this flask was placed 50 ml of toluene which has been driedwith a molecular sieve and deaerated. Therein was further placed 3.4mmols of vanadium oxytrichloride (VOCl₃) The resulting mixture wasthoroughly stirred. Thereto was gradually added 1.7 mmols of DBM. Thetemperature of the mixture was kept at 10° C. with stirring

(2) Polymerization procedure

A 3-liter autoclave equipped with agitating blades, a gas-introducingpipe, a thermometer, a pressure gauge, a non-conjugateddiene-introducing pipe and a catalyst-introducing pipe was sufficientlypurged with nitrogen, and then dried.

In this autoclave was placed 1.6 liters of dry liquid propylene. Throughthe gas-introducing pipe, dry ethylene and hydrogen were fed to theautoclave so that the pressure inside the autoclave was kept constant at12.0 kg/cm² G. The amount of hydrogen fed was 1/30 mole per mole ofethylene and this proportion was kept constant.

The temperature of the autoclave was kept constant at 20° C. by anexternal jacket. To the autoclave was fed 10.2 g of5-ethylidene-2-norbornene (ENB). With thoroughly stirring the contentsof the autoclave, 4.5 mmols of diethylaluminum monochloride (DEAC) wasadded thereto. To the resulting mixture was added 0.34 mmol of theDBM-modified VOCl₃ obtained in (1) above to start and copolymerization.

During the polymerization, the pressure and the temperature were keptconstant at 12.0 kg/cm² G and at 20° C., respectively.

After 30 min from the start of the polymerization, the supply ofethylene and hydrogen was stopped, and 100 ml of methanol was added tothe polymerization system to terminate the polymerization reaction.Then, a small amount of an antioxidant was added to the reactionmixture, and thorough stirring was conducted. Thereafter, ethylene,propylene ard water were removed, and steam stripping and drying wereconducted. The resulting copolymer was subjected to measurement ofyield, Mooney viscosity (ML₁₊₄ ¹⁰⁰° C.) propylene content and iodinevalue. The results are shown in Table 1.

(3) Measurement of gel content

About 2 g of the solid rubber obtained by drying the copolymer obtainedin (2) above was weighed (W₀ g), and placed in a flask together with 150ml of toluene. They were heated to reflux the toluene. One hour later,the toluene in the flask was removed by filtration through a wire net of200 mesh (Tyler) and the insoluble polymer remaining on the wire net wasdried for 24 hr under vacuum: and weighed (W₁ g).

The gel content was calculated using the following equation: ##EQU1##The result is shown in Table 1.

EXAMPLE 2 (1) Preparation of vanadium catalyst

A sufficiently dried flask was purged with nitrogen. Therein was placed50 ml of toluene which had preliminarily been dried and deaerated.Further, 3.4 mmols of VOCl₃ was placed, and the resulting mixture wasthoroughly stirred. Then, 5.1 mmols of dried n-butanol was graduallyadded to the mixture while bubbling the mixture with nitrogen andkeeping the mixture at 30° C., whereby the resulting hydrogen chloridewas removed.

The bubbling was continued for 30 min, and the preparation of catalystwas completed. (Hereinafter, the catalyst prepared under the aboveconditions is abbreviated to a CV catalyst.)

(2) Modification treatment

To the above CV catalyst was gradually added 1.7 mmols of dried DBM.This mixture was kept at a constant temperature of 5° C. with stirring.

(3) Polymerization procedure and measurement of gel content

Copolymerization and analysis were conducted under tne same conditionsas in Example 1, except that the amount of the DBM-modified CV catalystadded was 0.34 mmol in terms of VOCl₃.

The results are shown in Table 1.

EXAMPLE 3 (1) Modification treatment

A sufficiently dried flask was purged with nitrogen. Therein was placed80 ml of toluene which had preliminarily been dried with a molecularsieve and deaerated. Further, 0.75 mmol of vanadium diacetylacetonate[VO(AcAc)₂ ] was placed therein. The resulting mixture was thoroughlystirred. To the mixture was gradually added 0.38 mmol of dried DBM, andthe mixture was kept at a constant temperature of 20° C. with stirring.

(2) Polymerization procedure and measurement of gel content

Copolymerization and analysis were conducted under the same conditionsas in Example 1, except that the amount of ENB added was 15.3 g and thatof the amount of DBM-modified VO(AcAc)₂ added was 0.34 mmol.

The results are shown in Table 1.

EXAMPLE 4 (1) Modification treatment

VOCl₃ was modified by repeating the same procedure as in Example 1,except that the modifying compound was n-butyl salicylate (BS) and theamount of BS added was 2.05 mmols.

(2) Polymerization procedure and measurement of gel content

Copolymerization and analysis were conducted under the same conditionsas in Example 1.

The results are shown in Table 1.

EXAMPLE 5 (1) Modification treatment

VOCl₃ was modified by repeating the same procedure as in Example 1,except that the modifying compound was tri-n-butyl borate (TBB) and theamount of TBB added was 2.7 mmols.

(2) Polymerization procedure and measurement of gel content

Copolymerization and analysis were conducted under the same conditionsas in Example 1.

The results are shown in Table 1.

EXAMPLE 6

Modification treatment, polymerization procedure and measurement of gelcontent were all conducted in the same manner as in Example 2, exceptthat, in the polymerization procedure, 16.0 g of dicyclopentadiene (DCP)was added as a non-conjugated diene, and hydrogen was fed in aproportion of 1/10 mole per mole of ethylene.

The results are shown in Table 1.

EXAMPLE 7

Modification treatment, polymerization procedure and measurement of gelcontent were all conducted in the same manner as in Example 1, exceptthat the order of catalyst addition was reversed. That is, ENB was addedat first and then the DBM-modified VOCl₃ was added, after which DEAC wasadded, to start copolymerization.

The results are shown in Table 1.

EXAMPLE 8

Modification treatment, polymerization procedure and measurement of gelcontent were all conducted in the same manner as in Example 1, exceptthat the order of catalyst addition was reversed. That is, after ENB hadbeen added, DEAC and the DBM-modified VOCl₃ were fed simultaneously fromthe respective pipes, to start the copolymerization.

The results are shown in Table 1.

EXAMPLE 9

In this Example, VOCl₃ was modified with DBM in the presence of ENB, theresulting modified catalyst was contacted with DEAC to form an activeseed, and polymerization was conducted using the seed.

In the same procedure as in Example 1, ethylene, propylene and hydrogenwere fed to an autoclave, whereby the pressure and the temperatureinside the autoclave were kept constant at 12.0 kg/cm² G and 20° C.,respectively. ENB was at first charged into the autoclave, then VOCl₃and DBM were charged successively, and finally DEAC was charged, tostart the copolymerization.

The amounts of ethylene, propylene, hydrogen, ENB, VOCl₃, DBM and DEACadded were all the same as in Example 1.

The results are shown in Table 1.

COMPARATIVE EXAMPLE 1

The same procedure and analysis as in Example 1 were conducted, exceptthat no modifying compound was used.

The results are shown in Table 1.

COMPARATIVE EXAMPLE 2

The same procedure and analysis as in Example 2 were conducted, exceptthat no modifying compound was used.

The results are shown in Table 1.

COMPARATIVE EXAMPLE 3

The same procedure and analysis as in Example 6 were conducted, exceptthat no modifying compound was used.

The results are shown in Table 1.

COMPARATIVE EXAMPLE 4

DBM was used as a modifying compound as in Example 1; however,copolymerization was started without conducting a modification treatmentof VOCl₃. That is, in the same procedure as in Example 1, ENB was fed toan autoclave; while thoroughly stirring ENB, DEAC was added thereto;then, VOCl₃ and DBM were charged into the autoclave simultaneously fromthe respective pipes to start the copolymerization. The subsequentprocedure and analysis were conducted in the same manner as in Example1.

The results are shown in Table 1.

COMPARATIVE EXAMPLE 5

As in Comparative Example 4, VOCl₃, and DBM were used in thecopolymerization without conducting the modification of VOCl₃ with DBM.That is, in the same procedure as in Example 1, ENB was charged into anautoclave and then DEAC was fed. To the resulting mixture was addedVOCl₃ to start the copolymerization. Immediately thereafter, DBM wasadded. The subsequent procedure and analysis were conducted in the samemanner as in Example 1.

The results are shown in Table 1. In this Comparative Example, an activeseed was formed at the time of VOCl₃ addition, whereby copolymerizationproceeded. Addition of DBM in this state caused little reaction betweenVOCl₃ and DBM, and accordingly, substantially no modification wascaused.

COMPARATIVE EXAMPLE 6

As in Comparative Example 4, VOCl₃ and DBM were used in thecopolymerization without conducting the modification of VOCl₃ with DBM.That is, in the same procedure as in Example 1, ENB was charged into anautoclave; then DEAC, VOCl₃ DBM were charged simultaneously from therespective pipes; to start the copolymerization. The subsequentprocedure and analysis were conducted in the same manner as in Example1.

The results are shown in Table 1.

COMPARATIVE EXAMPLE 7

As in Comparative Example 4, VOCl₃ and DBM were used in thecopolymerization without conducting the modification of VOCl₃ with DBM.That is, in the same procedure as in Example 1, ENB was charged into anautoclave; then, DBM, DEAC and VOCl₃ were charged in this order to startthe copolymerization. The subsequent procedure and analysis were thesame as in Example 1.

The results are shown in Table 1. In this Comparative Example, at thetime of DEAC addition, DBM reacted with DEAC whereby the DBM required tomodify VOCl₃ was lost and substantially no modification of VOCl₃ wascaused.

                                      TABLE 1                                     __________________________________________________________________________    Results of Analysis                                                                  Non-         Modify-   Mooney                                                                             Propylene Gel                                     conjugated                                                                          Vanadium                                                                             ing   Yield                                                                             visco-                                                                             content                                                                             Iodine                                                                            content                                 diene compound                                                                             compound                                                                            (g) sity (wt %)                                                                              value                                                                             (wt %)                           __________________________________________________________________________    Example 1                                                                            ENB   VOCl.sub.3                                                                           DBM   52  86   40    29  Trace                            Example 2                                                                            "     CV     "     54  94   38    27  "                                Example 3                                                                            "     VO(AcAc).sub.2                                                                       "     48  80   36    27  "                                Example 4                                                                            "     VOCl.sub.3                                                                           BS    50  85   41    30  "                                Example 5                                                                            "     "      TBB   50  90   35    29  "                                Example 6                                                                            DCP   CV     DBM   40  48   38    12  "                                Example 7                                                                            ENB   VOCl.sub.3                                                                           "     49  80   37    28  "                                Example 8                                                                            "     "      "     54  89   40    31  "                                Example 9                                                                            "     "      "     48  77   41    32  "                                Comparative                                                                          ENB   VOCl.sub.3                                                                           --    50  80   42    26  18.6                             Example 1                                                                     Comparative                                                                          "     CV     --    54  96   38    28  12.7                             Example 2                                                                     Comparative                                                                          DCP   "      --    42  40   40    10  21.5                             Example 3                                                                     Comparative                                                                          ENB   VOCl.sub.3                                                                           DBM   49  80   42    28   8.5                             Example 4                                                                     Comparative                                                                          "     "      "     51  75   38    26  10.8                             Example 5                                                                     Comparative                                                                          "     "      "     52  88   36    29   6.4                             Example 6                                                                     Comparative                                                                          "     "      "     40  60   36    32  17.1                             Example 7                                                                     __________________________________________________________________________     Note:                                                                         Mooney viscosity . . .                                                        Propylene content . . . Measured by an infrared spectrometer.                 Iodine value . . . Measured by iodometry.                                     Trace . . . Less than 0.10% by weight.                                   

What is claimed is:
 1. A process for producing an olefin copolymerrubber, which comprises:copolymerizing ethylene, at least one α-olefinand at least one non-conjugated diene in a slurried state in aliquid-state α-olefin with substantially no solvent being present forthe resulting copolymer in the presence of a catalyst consisting of anorganoaluminum compound selected from the group consisting oftrialkylaluminum and a dialkylaluminum monohalide and a modifiedvanadium compound obtained by contacting a vanadium compound with atleast one modifying compound which is dibutyl maleate, or a borate ofthe formula: B(OR)₃, wherein R is a hydrocarbon group of 1 to 20 carbonatoms.
 2. The process according to claim 1, wherein the α-olefin has 3to 12 carbon atoms.
 3. The process according to claim 1, wherein theα-olefin is selected from the group consisting of propylene, 1-butene,4-methylpentene-1, hexene-1 and octene-1.
 4. The process according toclaim 1, wherein the α-olefin is propylene, 1-butene or a mixturethereof.
 5. A process according to claim 1, wherein the non-conjugateddiene is selected from the group consisting of dicyclopentadiene,tricyclopentadiene, 5-methyl-2,5-nobornadiene, 5-methylene-2-norbornene,5-ethylidene-2-norbornene, 5-isopropylidene-2-norbornene,5-isoproperyl-2-norbornene, 5-(1-butenyl)-2-norbornene, cyclooctadiene,vinylcyclohexene, 1,5,9-cyclododecatriene,6-methyl-4,7,8,9-tetrahydroindene, 2,2-dicyclopentenyl,trans-1,2-divinylcyclobutane, 1,4-hexadiene, 2-methyl-1,4-hexadiene and1,6-octadiene.
 6. The process according to claim 1, wherein thenon-conjugated diene is 5-ethylidene-2-norbornene, dicyclopentadiene ora mixture thereof.
 7. The process according to claim 1, wherein thetrialkylaluminum is triethylaluminum, triisobutylaluminum ortrioctylaluminum.
 8. The process according to claim 1, wherein thedialkylaluminum monohalide is diethylaluminum monochloride,diethylaluminum monobromide or diisobutylaluminum monochloride.
 9. Theprocess according to claim 1, wherein the borate is triethyl borate,tributyl borate, trihexyl borate, trioctyl borate, tri2-ethylhexylborate or tridodecyl borate.
 10. The process according to claim 1,wherein the vanadium compound is vanadium tetrachloride, vanadiumoxytrichloride, vanadium triacetylacetonate, a reaction product betweenvanadium oxytrichloride and an alcohol, vanadyl triethoxide, vanadyltri-n-butoxide, vanadyl di-n-butoxymonochloride, or vanadylethoxydichloride.
 11. The process according to claim 1, wherein thevanadium compound is vanadium oxytrichloride or oxyvanadiumdiacetylacetonate.
 12. The process according to claim 1, wherein themodified vanadium compound is obtained by adding a modifying compound toa vanadium compound in a solvent with stirring and then subjecting theresulting mixture to stirring at -60° C. to 100° C. for a given periodof time.
 13. The process according to claim 12, wherein the amount ofthe modifying compound added is 0.05 to 2.0 moles per mole of thevanadium compound.
 14. The process according to claim 12, wherein themodification of the vanadium compound is conducted in the presence ofthe monomers to be used in the polymerization reaction.
 15. The processaccording to claim 1, wherein the copolymerization is conducted at -50°C. to 100° C.
 16. The process according to claim 1, wherein thecopolymerization is conducted at -20° to 60° C.
 17. The processaccording to claim 1, wherein the amount of the organoaluminum compoundadded is 1 to 100 moles per mole of the vanadium compound.
 18. Theprocess according to claim 1, wherein the modifying compound is dibutylmaleate.
 19. The process of claim 1, wherein said dialkylaluminummonohalide is a dialkylaluminum monochloride.